<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="utf-8">
    </head>
    <body>
    	<div>1</div>
    	<div>2</div>
    	<div>3</div>
    </body>
    <script src="jquery-3.1.0.js"></script>
    <script>
    var  $dvs = $('div');
    var array1 = $dvs.get();
    var item1 = $dvs.get( 2 );//div3
    var item2 = $dvs.get( 3 );//undefined
    var item3 = $dvs.get( -1 );//div3
    var itme4 = $dvs.get( -2 );//div2
    var item5 = $dvs.get( -4 )//undefined
    </script>
</html>